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Memory

Memory. RAM and CACHE. RAM. Stands for Random Access Memory It is volatile in nature Loses its contents if the power is turned off Holds data and programs the CPU is using Main memory for the computer Scan be shared with other devices, such as video. Amount of RAM.

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Memory

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  1. Memory RAM and CACHE

  2. RAM • Stands for Random Access Memory • It is volatile in nature • Loses its contents if the power is turned off • Holds data and programs the CPU is using • Main memory for the computer • Scan be shared with other devices, such as video

  3. Amount of RAM • Measured in MegaBytes (MB) • The general rule of thumb is to install as much RAM as you can afford • Upgrading RAM can speed up a slow system

  4. Minimum Amounts of RAM • DOS 6.2 – 640 KB • Windows 3.x – 1 MB • Windows 95 – 8 MB • Windows 98 – 16 MB • Windows 2000 – 64 MB • Windows XP – 64 MB

  5. Types of RAM • SRAM • Static Random Access Memory • Uses transistors • Large and expensive, but fast • DRAM • Dynamic Random Access Memory • Uses capacitors • Small and affordable, but slower than SRAM

  6. Drawbacks of DRAM • The small capacitors need constant power to keep them from fading • This process of charging is called Refresh • Most DRAM needs to be refreshed every 2 ms

  7. DRAM Types • Started with DIP (Dual Inline Pin) socket types • Small amount of memory (>1MB) • Next advancement was SIPP (Single Inline Pin Package • Extinct because the pins were easy to bend and break

  8. DRAM Types • Changed styles to a SIMM (Single Inline Memory Module) • Small amounts of DIP chips on a single board • Used with 80286 – 80486 CPU’s • Two different styles – 30 pin and 72 pin

  9. 30 Pin SIMM • Has contacts on both sides of the module • Only contacts one side • Used in later 80286 and 80386 CPU’s

  10. 72 Pin SIMM • Has contacts on both sides of the module • Only contacts one side • Notch in the middle of the chip • Used in later 80386 and 80486 CPU’s

  11. FPM (Fast Page Mode) Arranges memory in rows and columns Older style of DRAM Used in few motherboards EDO (Extended Data Output) Allows access while an output is occurring Standardized DRAM Used in many motherboards Two Types Of 72 Pin SIMM’s

  12. 168 Pin DIMM • Next DRAM was the DIMM (Dual Inline Memory Module) • 168 pins long (84 contacts per side) • Also called SDRAM (Synchronous DRAM) • Runs at the same speed as the processor

  13. Newer Types of SDRAM • Next DRAM was the DDR-SDRAM • Double Data Rate Synchronous DRAM • Twice as fast as SDRAM • Current industry standard • Will not interchange with SDRAM

  14. Newest SDRAM • Rambus • Also called DRDRAM and RIMM • Runs at 400 Mhz, fastest of all RAM • All memory slots on the motherboard must be filled • Unused slots must have continuity modules installed

  15. Type of DRAM 30 pin SIMM’s 72 pin SIMM’s 168 pin DIMM’s DDR-SDRAM Rambus Amount Required 4 to a set 2 to a set Single modules Single modules All slots filled Installation of DRAM

  16. Installation of DRAM • Install DRAM starting from socket 0 or 1 • Some motherboards have a combination of socket types • Some of these sockets are shared, see the documentation • Use the same type of DRAM in the sets • Seat firmly until they snap into place

  17. Installation of DRAM • After installation, enter the CMOS and check for the installed memory • Watch the memory count and compare with the amount you installed

  18. (2) Parity 72 pin SIMM (2) non-parity 72 pin SIMM Parity 168 pin DIMM Non-parity 168 pin DIMM 72 bit 64 bit 72 bit 64 bit Bus Width of SDRAM

  19. Other Memory • VRAM (Video RAM) • WRAM (Windows RAM) • Both designed for video applications • Are double ported, meaning that 2 chips can access them at the same time • RAMDAC (RAM Digital to Analog Converter) • Used to convert digital signals to the monitor (for each color – red, green, and blue)

  20. CACHE memory • Two types of Cache • L1 (Level 1) which is mounted on the CPU chip • L2 (Level 2) which is mounted on the motherboard (or on the die with some CPU’s)

  21. L1 Cache • The fastest memory • Used to store frequently used information that the CPU needs • Part of the CPU chip • Uses SRAM technology

  22. 80486 80486DX4 Pentium Pentium MMX Pentium Pro Pentium 2 Celeron Pentium 3 8KB 16KB 16KB 32KB 16KB 32KB 32KB 32KB Standard L1 Cache Sizes

  23. L2 Cache • Next fastest memory • Used to store frequently used information that cannot be held in L1 cache • On the CPU board (Pentium Pro and Pentium 2) • On the motherboard • Uses SRAM technology

  24. 80486 80486DX4 Pentium Pentium MMX Pentium Pro Pentium 2 Celeron Pentium 3 0KB 0KB 0KB 0KB 256KB 512KB 0KB 512KB Standard L2 Cache Sizes

  25. COAST Modules • Some Pentium motherboards used L2 cache boards called COAST modules • Looked like a DIMM except they are shorter and taller • Used Pipeline-Burst mode

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